Hydraulic cylinder construction



0f-K 12. 1948- F. B. HUNTER HYDRAULIC CYLINDER CONSTRUCTION Filed Aug.20, 1945 l//lllll jaw/z i ffl/WEE,

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Patented Oct. l2, 1948 HYDRAULIC CYLINDER CONSTRUCTION Frank B. Hunter,Roscoe, Calif., asslgnor to Casimir A. M ikctta, Beverly Hills, Calif.

Application August 20, 1945, Serial No. 611,623

9 Claims. (Cl. 309-2) My invention relates to hydraulic cylinders andthe construction thereof in a manner permitting a hydraulic cylinderassembly oi' relatively precise design to be constructed oi.' partswhich need not be held to a close tolerance during the fabrication.

Hydraulic cylinders and rams have long been used in order to utilize thepressure exerted by hydraulic liquids for moving some mechanical deviceor other. If the stroke of the hydraulic cylinder need be long thesimplest means of effecting the long stroke is to provide acorrespondingly long hydraulic cylinder. The longer the cylinder inproportion to its diameter, the more care must be exercised in boringout the interior so that a piston sliding within the bore of thecylinder will have the necessary snug fit in order that all oi thehydraulic pressure on the liquid may be utilized Obviously, when a greatdeal of care is necessary in order to hold close tolerances in a longbore, the operation becomes correspondingly expensive. II the price ofdevices of this kind, particularly when made in large sizes, is to beheld within an economical range, the cost of producing cylinders with along bore need be held to a reasonable minimum. It is therefore amongthe 'objects of my invention to provide a hydraulic cylinderconstruction which will permit the assembly of a hydraulic cylinder ofprecise dimensions from parts where a' relatively greater latitude ispermitted in holding the critical dimensions.

Another object of my invention is to construct a hydraulic cylinder ofrelatively long bore from a number of dierent parts which, when suitablyassembled together and anchored in place, will provide a hydrauliccylinder having a long stroke capable of eiilciently utilizing hydraulicpressures of relatively great magnitude.

Still another object of my invention is to provide a hydraulic cylinderot relatively long stroke in proportionto its diameter which is adaptedto operate emciently upon a sudden demand so that hydraulic liquid underrelatively high pressure, when released by operation of a suitable trip,will be utilized at high efilciency in order to operate the cylinderthroughout the full length oi' its stroke.

A still further object of my invention is to provide in a hydrauliccylinder construction a means for connecting parts of the device formingthe cylinder walls to similar parts or to ends of the cylinder, whichmeans is capable of dispensing with a threaded connection and providesin its stead a connection which can be quickly clamped into place withsuilicient tightness to insure 2 against all leaks to which the cylindermaybe subjected and which can be as readily disconnected for servicingor replacement of parts of the device.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out i my claims and illustrated in theaccompanying drawings, in which:

Fig. 1 is a longtiudinal sectional view of the hydraulic cylinderassembly showing the piston in initial position.

Fig. 2 is a cross section taken on the line II-II of Fig. 1 through aconnection.

Fig, 3 is a section taken on the line III-III oi' Fig. 1 showing detailsof a trip operable with the device. f

Fig. 4 is a longitudinal sectional view of a modified form of my device.

In machining out the bores of cylinders of any kind, the operationcustomarily consists of an initial rough bore followed by one or morefinished bores so that the inside wall may be perfectly smooth and in atrue cylindrical shape. Practical difll'culties invariably arise, makingit impossible to make a perfectly cylindrical shape. For various usesdifferent tolerances may be permitted. In hydraulic cylinders widetolerances may sometimes be permissible if the hydraulic pressure is nothigh. In other instances where the hydraulic pressure is relatively highor where it is undesirable to have even a slight leak past the pistonwithin the cylinder, much closer tolerances are desirable and evennecessary. To hold close tolerances when the bore is relatively longnecessitates the use of expensive machinery and expensive machinesetups.

It will also be appreciated that almost any machining operations areexpensive as compared with casting operations. In view, however, of therelative cheapness of casting operations, where they can be utilized togood advantage, they permit a suiilcient saving of machining operationsso that a device utilizing some casting operations has a great advantageover a corresponding device which is made entirely by those machiningoperations.

In the embodiment chosen to illustrate my invention there is shown ahydraulic cylinder assembly which consists of a full length tubularliner III, the inside wall Il of which forms the bore of a hydrauliccylinder. The tubular liner may be or suitable commercial tubing drawnAwall of the liner.

to dimensions within permitted tolerances and cut to length as desired.Since the wall of the tubular liner may be o'f relatively thin gauge andincapable of providingjsuillcient strength to withstand hydraulicpressures customarily used, it is reinforced by the provision oi' acasing I2 at one end and a corresponding casing I3 at the other. Theinside wall of the respective casings may be formed by either roughboring or. on occasions, may be cast, since the dimensions need not beheld to a close tolerance so long as the liner is adapted to be' readilyinserted into the casing. The casing I2 is provided with an end I4having an axial aperture I5 in which is positioned a packing sleeve I3retained in place by a packing nut I1. Ring seals I8 and I9 are providedin order to make a fluid-tight fit.

The casing I3 is provided with an end portion of special construction inorder to accommodate a hydraulic release indicated generally by thereference character 2i. y

Within the liner is positioned a piston 22 which has a sliding fitwithin the inner wall II oi the liner and which is provided with a ringpacking 23-which has a sliding friction flt against the A piston rod 24,here shown lied form in Fig. 4 wherein the ring assembly is I cylinderwhere its'iorce can be exerted upon a Y face 44 of the piston 22.

The piston, however, is normally lockedin the y initial position shownin Fig. 1 so that although pressure exerted bythe hydraulic iluid may bepresent upon the piston, there will be no movement of the piston untilthe pressure exceeds ya certain predetermined igure.

tubular in section, is anchored at one end 25 to the piston and extendsoutwardly past the packing gland I6 and packing nut I1 within which ithas a sliding fit. At the outer end of the piston rod is provided a ring26 or other suitable vend of the hydraulic cylinder assembly is providedwith an apertured boss 21 by means of which it may be secured to somestationary portion of the machine.

The casings I2 and I3 are designed'to be connected together by somemeans other than threading.A As here shown, the casings are providedrespectively with flanges and 3| which are shown abutting against eachother and which have their respective inner corners 32 and 33 beveled soas to provide a rec'ess therebetween within which may be inserted apacking ring 34.

For holding the flanges in abutted relation there is provided a. pair ofsplit rings 35 having lateral' flanges 36- overlying the sides oi theilanges on the ends of the casings. When a ring, such as 35 is used, itis usually split-along a plane passing along the axis (diametrically) soas to form two halves, thereby giving rise to a pair of semi-circularsplit ring portions.

On the outer surfaces of the split rings is provided a rim portion 31.For holding the split rings'in position there is provided a continuousring 38 which surrounds the split rings in assembled position and whichbears at one edge against the rim 31. 'So that the continuous ring willremain' in place, the split rings are provided with a recessed portion39 into which may be positioned a snap ring 40.

When the split ring assembly is applied to the flanges of the casing inorder to hold them together. the packing ring 34 is compressed betweenthe inside beveled faces of the ilanges and the adjacent outside wall ofthe liner so as to be Huid-tight and prevent any hydraulic pressurewithin the interior of the liner from escaping at this connection. Aconstruction of this kind makes it unnecessary to have a snug iitbetween the outside wall of the liner and the interior of the casing.

- A similar construction is shown in the modin ui.

Within the closed end 20 is a transverse passage48 positioned at rightangles to the passage 41 which is axially disposed tothe bore of the ehydraulic cylinder member. The chamber is farmed at the intersection oftransverse passage 48 and the passage 41.

Positioned Within the passage 48 and extending from either end thereofis a sleeve 43, said sleeve beingl provided with a port in alignmentwith port and another port in alignment with the transverse passageway41. This sleeve is provided with a cap 50 at each end. Apair of opposingrelease pistons 5I is slidably positioned within the sleeve 49, thesepistons being spring pressed in the direction of the central chamber bymeans of coiled springs 53. Suitable packing rings 52 are carried byeach of the release pistons and external packing rings 54 completelyseal the sleeve in position.

In order to prevent the release pistons 5I from rotating and in order tokeep the ports of the sleeve 49 in alignment with the passageways 45 and41, each of the pistons is provided with a longitudinal slot 55 adaptedto slidably receive dog ends 56 of set screws 51. These dog screws alsoprevent the release pistons from coming into complete contact.

The end oi' each release piston is specially shaped in that it isprovided with a semicircular flange 58 which is designed to engagelwithin a portionof an annular recess 53 located beneath a head B9 of apin 60. It will be noted that the pin has a flange 3| resting againstthe face 44 of the piston. The pin extends through the piston and into athreaded engagement 62 with the piston rod 24. The pin is thus securelyanchored in place upon the piston. Ample space is provided around theloutside end of the pin so that hydraulic fluid may pass freely along its,sides through passage 41 and into the hydraulic'cylinder wherein itpresses against the face 44 of the piston. At the other end I4 of thecylinder there is provided a second port 33. -v

In operation. the piston, in initial position, is located at the end ofthe cylinder member as shown in Fig. 1 wherein the pin is locked byreason of the fact that. the springs 53 press the release pistonsinwardly so that the ends engage beneath the head 59 of the pin. vFluidunder pressure is then admitted into the port 45 from 4which it isenabled to pass through the. bore- 41 into the cylinder where it sets upa pressure against the piston. As the pressure builds up the piston willnot move but will remain xed in position so long as the release pistonsengage the pin. After fluidl pressure has built up to' an amountsufilcient to overcome the pressure of the springs 53, the releasepistons will be pushed outwardly 'but of' engagement with the head ofthe pin. When this is accomplished, the pin will be released and thepiston 22 will be moved from the position shown in Fig. 1 to a positionadjacent the other end of the cylinder member. Meanwhile, should therebe any fluid within the cylinder on the opposite side o thepistonit maybe exhausted outwardly through the port 63. To return the piston to itsinitial position is necessary only to reverse the flow of the pressureiluid so that it enters the port 63, driving the piston from therighthand end of the cylinder as viewed in Fig.v 1 to the lefthand end.As the piston is pushed against the lefthand end, the head 59 of the pinpenetrates'into the space left remaining between opposite ends of therelease pistons forcing them far enough apart so that the head of thepin may be completely inserted in order for the annular recessadjacentgthe head to be re-engaged by the appropriate portions of therelease pistons. It will be noted from this that the cylinder may be setto operate at a high, suddenly released, instantaneous pressure, eventhough the piston stroke is long.

It will be noted from the description given that the cylinder (orcylinder portions) are free from threads cut thereinto. In themodification shown Iin Fig.' 1v the end pieces are an integral part ofthe cylinder. In the modification shown in Fig. 4, the end pieces aresimply but eiectively connected to the cylinder. Here two split ringsare used. By eliminating threaded ends, the problems ordinarilyencountered in cutting threads precisely so that an engaging cap will bein proper alignment with the axis of the cylinder are eliminated. Theboring of the cylinder and the cutting off of the ends of such cylindermay be accomplished upon the same machine tool and result in end faceswhich are perpendicular to the axis of the cylinder. Any slightmisalignment of the cylinder sections I2 and I3 is nullifled by thecontinuous inner liner.

It will also be evident that cylinders constructed in accordance withthis invention may be dismantledA while one end of the cylinder is stillattached to the structure which carries the cylinder. It is onlynecessary to remove the snap ring 40 and slip the retaining ring 38 ofithe split ring sections 35 in order to remove one of the cylinderportions I2 or I'3.

In actual practice it has been found that the construction shown is oflighter weight than that available heretofore. It will be understood,however, that the locking mechanism, including pin 60, release pistons5I, etc., need not be employed unless the function or use to which thepiston is to be put renders desirable the utilization of a lockingmechanism. Although specific reference has been made to hydrauliccylinders, it will be obvious that the construction here shown may beused not only with hydraulic liquids but also with pneumatic uids.

I claim:

1. A hydraulic cylinder assembly comprising a full length tubular llinerforming a central bore of relatively precise dimension, structuralcasing members surrounding the liner including a cylindrical body memberand end members and means for connecting a pair of adjacent memberscomprising opposed and abutting flanges thereon, a

recessed portion between said members and the liner, a packing in therecessed portion adapted to be compressed against the exterior of theliner, a split ring assembly adapted to enclose the nanges 'throughouttheir circumferences, a oon- 6 tinuous retaining ring surrounding thsplit ring assembly and an annular circumferential rim on the split ringassembly adapted to retain the con 'tinuous ring in place.

2. A hydraulic cylinder assembly comprising end members and acylindrical member having a bore therein for reception of a slidablymounted piston in the bore having a piston rod thereon extending fromone end, and means for connecting said members together comprisingopposed and abutting anges on adjacent members recessed at the innercorner forming a space therebetween, a split ring assembly adapted toenclose the iianges throughout their circumferences, a circumferentialexterior rim on the ring assembly, a continuous ring retained by the rimand surround-ing thespli-t ring assembly, an annular circumferentialrecess in the side of the split ring assembly oppositel the rim and aspring snap ring adapted to be retained in the recess vfor anchoring thecontinuous ring in place.

3. A hydraulic cylinder assembly comprising a full length Itubular linerforming a central bore of relatively precise dimension, a pistonslidably mounted in the borehaving a piston rod thereon extending fromone end, a structural casing surrounding the liner comprising elementseach of less than the full length of the liner 4and having a closed endthereon forming one end of the cylinder assembly and means forconnecting the open ends comprising Opposed and abutting flanges con thestructural elements, a packing between the ends of the structural casingelements and the exterior of the liner, and a retainer cooperable withthe flanges for anchoring 'the ends of the structural casing elements inplace.

I4. A hydraulic cylinder assembly comprising a full length tubular linerforming a central bore ofrelatively precise dimension, a piston slidablymounted in the bore having a piston rod rthereon extending from one end,a structural casing surrounding the liner with a clearance therebetweencomprisingelements each of substantially one half the length of theliner and having a closed end thereon forming one end Yof the cylinderassembly and means for connecting the open ends comprising opposed andabutting flanges on the structufral elements, a ring packing ad-apted tobe compressed between rthe ends of the structural casing elements andthe exterior of the liner, a split ring assembly adapted to enclose theflanges .throughout their circumferences, and means for retaining thering assembly in place. l

5. A hydraulic cylinder assembly comprising a full length tubular linerforming a centra-1 bore of relatively precise dimension, a pistonslidably mounted in the bore having a piston rod thereon extending fromone end, a structural casing surrounding the liner with a clearancetherebetween comprising elements each of substantially one half thelength of .the l-iner and having a closed end thereon forming one end ofthe cylinder assembly and means for connecting the open ends comprisingopposed and abutting flanges on the elements of the structural casingrecessed at the inner corner forming a space therebetween, a ringpacking in the space formed by the recesses adapted to be compressedagainst the exterior of the liner, a split ring assembly adapted toenclose the flanges throughout their circumferences, a circumferentialexterior rim on the ring assembly, a continuousming retained by the rimand surrounding the split ring assembly, an annular circumferentialrecess in the side of the split ring assembly opposite the rim and aspring snap ring adapted to .be retained in the recess for anchoring thecontinuous ring in place. Y

6. In a iluid pressure actuating cylinder construction: a hollowcylinder provided with a closed end and an open end. an outwardlyextending flange at said open end, said ange having a face lying in aplane transverse to the cylinder axis, a closure member for the open endof the cylinder,

- said closure member having an outwardly extending ilange adapted toabut the first-named flange, e split ring of channel section adapted tograsp the abutting nanges, a continuous retainer ring slidable upon saidsplit ring t hold the latter in iange-grasping position, and releasablemeans for holding the retainer ring upon the split ring.

7. In a iluid pressure actuating cylinder construction: a pair ofcylinder portions each provided with a closed end and an open end and anoutwardly extending flange at said open end, whereby said cylinderportions Vmay be placed in alignment with said anges in contact, a splitclamping ring of channel section adapted to grasp said anges andrestrain said cylinder portions from relative axial movement, acontinuous unbroken retainer ring slidable upon said clamping ring in anaxial direction and releasable means for holding the retainer ring uponthe clamping ring.

8. In a iluid pressure actuating cylinder construction: -a pair ofcylinder portions each provided with a closed end and an open end and anoutwardly extendingA ilange -at said open end, whereby said cylinderportions may be placed in alignment with said vflanges in contact, asplit clamping ring of channel section adapted to grasp said anges andrestrainsaid cylinder portions from relative axial movement, acontinuous retainer ring slidable upon said clamping ring, releasablemeans for holding the retainer ring upon cylinder vportions andextending between the closed ends thereof.

9. In a uuid pressure actuating cylinder Yon struction: a pair ofcylinder portions each provided with a closed end and an open end-andvan outwardly extending ange at said open end,

-whereby said cylinder portions may be placedin alignment with saidvflanges in contact. a split clamping ring of channel section adapted tograsp said ilanges andrestrain said cylinder portions from relativeaxial movement, a continuous retainer ring slidable upon said clampingring, releasable means for holding the retainer ring upon the clampingring, a tubular. liner within said cylinder portions and extending`between` the -closed ends thereof and a sealing ring carried between thetubular linerland said cylinder portions in the region of said joint. Av

' FRANK B. HUNTER.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Brown May -23, 1944

